can somebody please explain in plain english how to read channels properly in order to use them to fix an image
Can you please restate this question? Not knowing what you want to do, it makes it hard to help you
and why are they represented in grayscale?
Because you did not check "Display Color Channels in Color" in your preferences (which I do not recommend as it makes the yellow channel unvieable for all practical purposes.)
Channels are represented in Grayscale because that’s the best way to do what they do – represent the density of color in each channel. It also corresponds to the color separation negatives that were used in commercial printing prior to the DTP printing, providing a good visual on screen version of what you would see in separation neg.
In RGB, the channels correspond to what you would see if you shot three pin registered black and white photos, through a Red, Green and Blue cutoff filter and then combined them back together to make a full color image. Think original three strip Technicolor, but you could do it with a still camera too.
In concert with Rene’s remarks, the operative word "fix" can mean anything. There are at least three ways to do anything in photohsop so it is entirely possible that channels is not the best way (then again, maybe it is).
If you would like some image specific help, post the image on one of the free sites like www.pixentral.com or www.imageshack.us; It will also be helpful to include what you find wrong with the image and it’s intent (web, print, etc.).
Channels do what they do – show the values as recorded and as explained above it has a strong historical link with past printshop methodology and possibly links well with how sensors and displays work too.
That is all channels do, full stop, dead-end.
Now how that information is interpretted and put to use that may be what you are seeking for. If so, there is no unique one-way simple answer.
For example: Layers do not fix an image – full-stop. All the editing options/tools/blending/adjustments available do not fix images either.
It is IMHO an application of those tools after interpreting what is presented onscreen coupled with experience and maybe even guesswork that fixes images. The Tools do not do it on their own IMHO
Rene Walling,
Now, would you answer the "Ctrl+Click" guy? You’re on a roll….Nyahaahaa.
Angus,
You’d better read up on channels in the manual. It’s your negative or all the information that you have to work with.
By "read" it means LOOK at the channels independently and interpret how each separately affects the composite. You are being asked to say what information each channel holds for that particular image,
Notice that the blue channel often carries all the noise and crap so avoid sharpening this channel. But also notice that the blue channel usually has the highest contrast and so is great for making easy selections.
Notice that a caucasion’s skin detail is held in the red channel and is the best place to obliterate a zit without losing detail in the composite.
Notice that the image detail is held in the red or green channel depending on you image –portrait or landscape.
Many of the utility filters –such as sharpen, noise, and blur–work on that greyscale information –can be selectively used on a particular channel for a purpose. Say you have a night image and the noise is held in the blue channel, while all the fireworks are held in the red channel. Sharpen the red then blur and darken the blue channel and so improve the composite.
The channels allow you to control information. So figure out what you want to do. Go look in the channels for the information you need. Then serously putter in the channel in order to control that information. Anything goes.
It’s the place to seriously putter: include Channels, Channel Mixer, Calculations or Apply image in this scenario.
ok – that’s more like it – thanks
If it’s any consolation Angus were I given stone, hammer and chisel I guess I could make quite good stone chips
Were someone else given the same tools they probably could produce a statue that is pondered and wondered about for centuries
